LOCATION SHELLWOOD IAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Cumulic Hapludolls
TYPICAL PEDON: Shellwood sandy loam - in a cultivated field on nearly level floodplains adjacent to the Shell Rock River. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; black (10YR 2/1) sandy loam, very dark gray (10YR 3/1) dry; weak very fine and fine granular structure; very friable; strong effervescence; mildly alkaline; abrupt smooth boundary.
A1--9 to 17 inches; black (10YR 2/1) sandy loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure parting to weak very fine granular; very friable; strong effervescence; mildly alkaline; gradual smooth boundary.
A2--17 to 29 inches; black (10YR 2/1) sandy loam, very dark gray (10YR 3/1) dry; weak very fine subangular blocky structure parting to weak very fine granular; very friable; strong effervescence; mildly alkaline; gradual smooth boundary.
A3--29 to 46 inches; black (10YR 2/1) sandy loam, very dark gray (10YR 3/1) dry; weak very fine and fine subangular blocky structure; very friable; many roots; strong effervescence; moderately alkaline; gradual smooth boundary.
AC--46 to 56 inches; very dark gray (10YR 3/1) sandy loam dark gray (10YR 4/1) dry; weak fine subangular blocky structure; very friable; strong effervescence; mildly alkaline; gradual smooth boundary.
2C--56 to 60 inches; very dark brown (10YR 2/2) sandy loam, dark grayish brown (10YR 4/2) dry; massive; very friable; violent effervescence; moderately alkaline.
TYPE LOCATION: Floyd County, Iowa, about 2 miles southeast of Nora Springs; 2,300 feet south and 1,120 feet east of the center of Sec. 20, T. 96 N., R. 18 W.
RANGE IN CHARACTERISTICS: Solum thickness typically is between 40 and 60 inches. The mollic epipedon ranges from about 40 to 70 inches. The 10- to 40-inch control section averages between 12 and 18 percent clay and between 52 and 75 percent sand. Sand size is mostly fine and medium.
The A horizon has value of 2 or 3, and chroma of 1 or 2. It typically is sandy loam, but in some pedons it is fine sandy loam.
The AC horizon and the B horizon, where present, have value of 3 or 4 and chroma of 1 or 2.
The C horizon has hue of 10YR or 2.5Y, value of 2 to 4, and chroma of 2 or 3. It typically is sandy loam but ranges to loamy sand.
COMPETING SERIES: These are the Ankeny, Disco, Eyota, Hanlon, and Lomax series. These soils do not have free carbonates in the control section. In addition, Ankeny soils have a mollic epipedon that is 24 to 36 inches thick and has a B horizon that is 3 or more in chroma. Disco soils have a thinner mollic epipedon. Eyota soils have a silt loam or loam 2B horizon with chroma of 3 or 4. Lomax soils have chroma of 3 or more in the major part of the B horizon and average less than 52 percent sand in the 10- to 40-inch control section.
GEOGRAPHIC SETTING: Shellwood soils are on floodplains. Slope gradients are dominantly 0 to 3 percent. These soils formed in dark colored moderately coarse textured alluvium containing 52 to 75 percent sand. Mean annual temperature ranges from about 44 to 52 degrees F, and mean annual precipitation ranges from about 28 to 34 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Calco and Du Page soils. Du Page soils are on nearly level adjacent flats. They contain more clay and less sand in the solum. Calco soils occur on lower-lying flood plains and also contain more clay and less sand.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is medium or slow. Permeability is moderately rapid. It is subject to flooding and has a seasonal high watertable at depths of 3 to 5 feet.
USE AND VEGETATION: Commonly cropped to corn, hay, small grain, and soybeans. Flooding is occasional and the seasonal high watertable is at 3 to 5 feet. Native vegetation was prairie grasses.
DISTRIBUTION AND EXTENT: North central Iowa.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Floyd County, Iowa, 1989. The name is coined from the adjacent Shell Rock River.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to a depth of 56 inches. (Ap, A1, A2, A3 and AC horizons)